This invention generally relates to the art of optical fibers and, particularly, to an optical fiber interconnection system. Still further, this invention relates to an interconnection system for optical fibers between a flat fiber optic circuit and a fiber optic connector, along with a method of fabricating the system.
Fiber optic circuitry is increasingly being used in electronics systems where circuit density is ever-increasing and is difficult to provide with known electrically wired circuitry. An optical fiber circuit is formed by a plurality of optical fibers carried by a dielectric or substrate and the ends of the fibers are interconnected to various forms of connectors or other optical transmission devices. A fiber optic circuit may include a simple cable which includes a plurality of the optical fibers surrounded by an outer cladding or tubular dielectric. On the other hand, a more sophisticated optical backplane or flat fiber optic circuit is formed by a plurality of optical fibers mounted or routed on a substrate in a given pattern or circuit geometry. Optical backplanes are used to interconnect optical circuit components which transmit signals optically, as well as electrical circuit components, wiring boards, modules and/or integrated circuits. When an optical backplane interconnects electrical components, the electrical energy of each component is translated to optical energy which is transmitted by optical fibers on the optical backplane to another electrical component where it is translated back to electrical energy for transmission to the other electrical component. Optical fibers can transmit much more information than electrical conductors and with significantly less signal degradation.
In fabricating flat fiber optic circuits or backplanes, the individual optical fibers often extend beyond an edge of the substrate whereby the individual fibers can be manipulated during termination of the fibers to various connectors or other fiber optic transmission devices. During termination, problems often are encountered. Specifically, whenever a fiber from the flat circuit is terminated to a connector, there is a possibility of the fiber breaking. The fibers also may be broken after termination to the connector(s) during handling and during polishing of the connector end face. If a single fiber on the circuit is broken, or if an unacceptable polishing process is performed on any one connector, the entire circuit and connectors must be discarded, resulting in a considerable loss of time and expenses.
The present invention is directed to solving these problems by providing a system which protects the fibers from breaking during assembly and during subsequent handling. The system also solves the problem of having to discard an entire circuit assembly should the polishing process on an individual connector be faulty.
An object, therefore, of the invention is to provide a new and improved optical fiber interconnection system.
Another object of the invention is to provide a new and improved interconnection system for fibers between a flat fiber optic circuit and a fiber optic connector.
A further object of the invention is to provide a method of fabricating the interconnection system.
In the exemplary embodiment of the invention, the interconnection system includes a flat fiber optic circuit having a flat substrate with a peripheral edge. A tail portion of the substrate projects from the peripheral edge to a distal end of the tail portion. A plurality of first optical fibers are mounted on the flat substrate and on the tail portion thereof. Ends of the first fibers extend beyond the distal end of the tail portion. A fiber optic connector is terminated, polished and tested to a plurality of second optical fibers. Ends of the second fibers extend from the connector to a connecting point for connection to the ends of the first fibers from the flat fiber optic circuit. A protective shroud is positioned over the connecting point between the ends of the first and second fibers. The protective shroud is fixed to the projecting tail portion of the substrate of the flat fiber optic circuit.
As disclosed herein, the protective shroud includes a rigid member extending at least from a point spaced inwardly of the distal end of the tail portion of the substrate to beyond the connecting point between the ends of the first and second fibers. The rigid member may be fabricated of glass. A plastic layer is positioned over the rigid member. The plastic layer is heat shrunk onto the rigid member, onto the distal end of the tail portion and onto the connected ends of the first and second fibers.
The invention contemplates that the substrate of the flat fiber optic circuit be a flat flexible substrate. Preferably, the ends of the first and second fibers are connected by a fused connection.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.